(mē'tē-ə-rīt') A meteor that reaches the Earth's surface because it has not been burned up by friction with the atmosphere. Meteorites are believed to be fragments of comets and asteroids. ◇ Meteorites that consist mostly of silicates are called stony meteorites and are classified as either chondrites or achondrites. ◇ Meteorites that consist mostly of iron are called iron meteorites. ◇ Meteorites that consist of a mixture of silicates and iron are called stony-iron meteorites.